def createFrameModel():
"""Create the Finite Element Model.
It is supposed here that the Geometry has been created and is available
as a global variable F.
"""
wireframe()
lights(False)
# Turn the Formex structure into a TriSurface
# This guarantees that element i of the Formex is element i of the TriSurface
S = TriSurface(F)
nodes = S.coords
elems = S.elems # the triangles
# Create edges and faces from edges
print "The structure has %s nodes, %s edges and %s faces" % (S.ncoords(),S.nedges(),S.nfaces())
# Create the steel structure
E = Formex(nodes[S.getEdges()])
clear()
draw(E)
# Get the tri elements that are part of a quadrilateral:
prop = F.prop
quadtri = S.getFaceEdges()[prop==6]
nquadtri = quadtri.shape[0]
print "%s triangles are part of quadrilateral faces" % nquadtri
if nquadtri > 0:
# Create triangle definitions of the quadtri faces
tri = Connectivity.tangle(quadtri,S.getEdges())
D = Formex(nodes[tri])
clear()
flatwire()
draw(D,color='yellow')
conn = connections(quadtri)
print conn
# Filter out the single connection edges
internal = [ c[0] for c in conn if len(c[1]) > 1 ]
print "Internal edges in quadrilaterals: %s" % internal
E = Formex(nodes[S.getEdges()],1)
E.prop[internal] = 6
wireframe()
clear()
draw(E)
# Remove internal edges
tubes = S.getEdges()[E.prop != 6]
print "Number of tube elements after removing %s internals: %s" % (len(internal),tubes.shape[0])
D = Formex(nodes[tubes],1)
clear()
draw(D)
# Beam section and material properties
b = 60
h = 100
t = 4
b1 = b-2*t
h1 = h-2*t
A = b*h - b1*h1
print b*h**3
I1 = (b*h**3 - b1*h1**3) / 12
I2 = (h*b**3 - h1*b1**3) / 12
I12 = 0
J = 4 * A**2 / (2*(b+h)/t)
tube = {
'name':'tube',
'cross_section': A,
'moment_inertia_11': I1,
'moment_inertia_22': I2,
'moment_inertia_12': I12,
'torsional_constant': J
}
steel = {
'name':'steel',
'young_modulus' : 206000,
'shear_modulus' : 81500,
'density' : 7.85e-9,
}
print tube
print steel
tubesection = ElemSection(section=tube,material=steel)
# Calculate the nodal loads
# Area of triangles
area,normals = S.areaNormals()
print "Area:\n%s" % area
# compute bar lengths
bars = nodes[tubes]
barV = bars[:,1,:] - bars[:,0,:]
barL = sqrt((barV*barV).sum(axis=-1))
print "Member length:\n%s" % barL
### DEFINE LOAD CASE (ask user) ###
res = askItems([('Steel',True),
('Glass',True),
('Snow',False),
('Solver',None,'select',['Calpy','Abaqus']),
])
if not res:
return
nlc = 0
for lc in [ 'Steel','Glass','Snow' ]:
if res[lc]:
nlc += 1
NODLoad = zeros((nlc,S.ncoords(),3))
nlc = 0
if res['Steel']:
# the STEEL weight
lwgt = steel['density'] * tube['cross_section'] * 9810 # mm/s**2
print "Weight per length %s" % lwgt
# assemble steel weight load
for e,L in zip(tubes,barL):
NODLoad[nlc,e] += [ 0., 0., - L * lwgt / 2 ]
nlc += 1
if res['Glass']:
# the GLASS weight
wgt = 450e-6 # N/mm**2
# assemble uniform glass load
for e,a in zip(S.elems,area):
NODLoad[nlc,e] += [ 0., 0., - a * wgt / 3 ]
nlc += 1
if res['Snow']:
# NON UNIFORM SNOW
fn = 'hesperia-nieve.prop'
snowp = fromfile(fn,sep=',')
snow_uniform = 320e-6 # N/mm**2
snow_non_uniform = { 1:333e-6, 2:133e-6, 3:133e-6, 4:266e-6, 5:266e-6, 6:667e-6 }
# assemble non-uniform snow load
for e,a,p in zip(S.elems,area,snowp):
NODLoad[nlc,e] += [ 0., 0., - a * snow_non_uniform[p] / 3]
nlc += 1
# For Abaqus: put the nodal loads in the properties database
print NODLoad
PDB = PropertyDB()
for lc in range(nlc):
for i,P in enumerate(NODLoad[lc]):
PDB.nodeProp(tag=lc,set=i,cload=[P[0],P[1],P[2],0.,0.,0.])
# Get support nodes
botnodes = where(isClose(nodes[:,2], 0.0))[0]
bot = nodes[botnodes]
pf.message("There are %s support nodes." % bot.shape[0])
# Upper structure
nnodes = nodes.shape[0] # node number offset
ntubes = tubes.shape[0] # element number offset
PDB.elemProp(set=arange(ntubes),section=tubesection,eltype='FRAME3D')
# Create support systems (vertical beams)
bot2 = bot + [ 0.,0.,-200.] # new nodes 200mm below bot
botnodes2 = arange(botnodes.shape[0]) + nnodes # node numbers
nodes = concatenate([nodes,bot2])
supports = column_stack([botnodes,botnodes2])
elems = concatenate([tubes,supports])
## !!!
## THIS SHOULD BE FIXED !!!
supportsection = ElemSection(material=steel,section={
'name':'support',
'cross_section': A,
'moment_inertia_11': I1,
'moment_inertia_22': I2,
'moment_inertia_12': I12,
'torsional_constant': J
})
PDB.elemProp(set=arange(ntubes,elems.shape[0]),section=supportsection,eltype='FRAME3D')
# Finally, the botnodes2 get the support conditions
botnodes = botnodes2
## # Radial movement only
## np_fixed = NodeProperty(1,bound=[0,1,1,0,0,0],coords='cylindrical',coordset=[0,0,0,0,0,1])
## # No movement, since we left out the ring beam
## for i in botnodes:
## NodeProperty(i,bound=[1,1,1,0,0,0],coords='cylindrical',coordset=[0,0,0,0,0,1])
## np_central_loaded = NodeProperty(3, displacement=[[1,radial_displacement]],coords='cylindrical',coordset=[0,0,0,0,0,1])
## #np_transf = NodeProperty(0,coords='cylindrical',coordset=[0,0,0,0,0,1])
# Draw the supports
S = connect([Formex(bot),Formex(bot2)])
draw(S,color='black')
if res['Solver'] == 'Calpy':
fe_model = Dict(dict(solver='Calpy',nodes=nodes,elems=elems,prop=PDB,loads=NODLoad,botnodes=botnodes,nsteps=nlc))
else:
fe_model = Dict(dict(solver='Abaqus',nodes=nodes,elems=elems,prop=PDB,botnodes=botnodes,nsteps=nlc))
export({'fe_model':fe_model})
print "FE model created and exported as 'fe_model'"
